Internal combustion engine



Aug) 22, 1939.

M. GERLACH INTERNAL COMBUSTION ENGINE Filed Sept. 27, 1937 2Sheets-$heet 1 Aug. 22, 19 39. M. GERLACH INTERNAL COMBUSTION ENGINE 2Sheets-Shed 2 Filed Sept. 27, 1937 obtain a higher 'efliciency.

Patented Aug. 22, 1939 2,170,020 INTERNAL COMBUSTION ENGINE Manfred'Gerlacll, Aken-on-the-Elbe, Germany, I minor to JunkersFlugzeugand-Motorcawerke Aktlengesellschalt, Deccan, GermanyA'ppllcatlonseptember 21,1937, Serial No.'185,869. m can September30,1936

claims (craze-551 This invention relates to internal combustion.

engines and more especially to that kind of engine in which theadmission of air or fuclorj both iscontrolled by the piston governingthe intake ports.

It is anobjectof my invention to improve the operation of such enginesby improving the form and arrangement of these intake ports sons toOther objects of this invention will appear as the specificationproceeds.

In internal combustion engines the area of passage for the mediumentering the cylinder has already been subdivided into a great number of'17- small ports which are arranged in a plurality of axially spaced'circular sections and the axes of which are disposed at an angle to thecylinder radii. Hitherto intake ports of this kind were so arranged thatthe axes of all ports werearranged at the same angle relative to thecylindrical inner-wall of the cylinder.

Practical experience has shown that even in cylinders formed with intakeports of the k nd described the scavenging operation does not pro'-'ceed in an altogether satisfactory manner. This is substantially due tothe circumstance that in the scavenging step two requirements must befulfilled which appear to counteract each other,

Whenoisplacing the waste gases by the fresh gases these two'kinds ofgases should mix with each other as little as possible in order that thespent gases be removed from the cylinder as completely as possible. I

On the other hand in order that the air of combustion admittedinto thecylinder be able to intimately permeate the fuel as required for asatisfactory combustion, it is important, quite especially in the caseof engines operated with fuel injection, to impart to the fresh gases avigorous eddying movement'whlch shall even continue after the scavengingoperation has come to an end. I

If intake ports are provided, the walls of'whlch are directedsubstantially tangentially to the inner cylinder wall, a vigorouseddying movement is obtained, but owing to the centrifugal forcescreatedby this movement the cooler and consequently heavier fresh gases areforced towards the outside, while the warmer and consequently lighterwaste gases are left in the central portion of the cylinder, so thathere a core of hot waste-"gases is retained.

If, in order a avoid as far as possible the for-' mation of such core,the intake ports are arranged with their axes directedmore radially, theeddying movement is reduced and the feed of fresh air to the fueladmitteddnto the cylinder wjll'be unsatisfactory, so that only a smallerquantity of fuel can be brought to complete combustion and the engineoutput will be lower. 5

This invention is intended to obviate these drawbacks by providingscavenging means which allow fulfilling the two requirements definedabove, viz. a complete scavenging of the cylinder and the creation of avigorous eddying movement in the fresh charge, although these tworequirenients "appear to contradict each. other to a certain extent.

In accordance with this invention the perforations of the cylinder wall,which form the intake ports and which are arranged in more than twoaxially spaced circular rows, are so disposed and formed, that the axesof the ports forming the individual rows ,extend at different anglesrelative to a radius intersecting the inner opening of the port, theangle enclosed between the port inthe cylinder.

The axes. of the ports in the diilerent rows may further be inclineddifferently relative to the cylinder axis, their inclination towards thecombustlon space being the greater, the closer the ports are disposedrelative to the combustion space. The axes of the ports. spaced fartheraway from 39 the combustion space may extend normally to the cylinder'axis or may even be directed somewhat towards the outer end of thecylinder.

In the drawings afiixed to this specification and forming part thereofFigs. 1 to 5 illustrate diagrammatically by way of. example a workingcylinder, embodying my invention, of an internal combustion engine o'fthe opposed piston type,

Fig. 1 being'an axial section of the cylinder and the pistonsreciprocating therein, while Figs. 2 to 5 are cross sections on thelines 11-11, IIIIII, IV-IV and VV respectively in ,Fig. 1, of the rowsof intake ports. 1

Figs. 6 to 8' are axial cylinder sections serving to illustratediagrammatically the operation of the invention.

formed by a plurality of circular rows of perforations 3, 8, Band 6,respectively, arranged in series in the axial direction of the cylinderwall.

The perforations 3 which adjoin the combustion space forming the middlepart of the cylinder are so arranged that their axes, if viewed in thelongitudinal section shown in Fig. l, are strongly inclined relative tothe cylinder axis in the direction towards the combustion space, while,if viewed in cross section (Fig. 2), they considerably deviate from theradial direction, being directed more tangentially. In the other rows ofports 4, 5 and 6 the port axes are gradually less inclined relative tothe combustion space, so that the axes of the ports constituting the row5 extend normally to the cylinder axis, while the axes of the outermostrow 6 are even slightly inclined towards the other side, i. e. towardsthe outer end of the cylinder. If viewed in cross section, asillustrated by Figs. 3 to 5, the deviation of the direction of the portaxes from the radial direction is the smaller, the farther outwardly therow of ports is arranged, and in row 6 the port axes are even radiallydirected.

During an outward stroke of the piston Ill controlling the intake ports(Fig. 6) the ports 3 of the row adjoining the combustion space are thefirst to be uncovered. The fresh gases accumulated in the reservoir 1(Fig. 1) under a certain increased pressure now enter the cylinderthrough the ports 3 and displace a part, corresponding to their volume,of the waste gases in the cylinder by expelling them through the exhaustports which were already, at least partly, uncovered. The path throughwhich these fresh gases travel, extends, in accordance withthe directionof the axes of the ports 3, in the form of a high pitch helix in theouter part of the cylinder space. As indicated in Fig. 6, the freshgases thus fill an outer annular zone a with a vigorous longitudinal andcircular flow, while the core b is formed substantially by stationarywaste gases.

The piston ill in continuing its outward stroke uncovers the ports I.Since the axes of these ports arearranged at a larger angle to thecylinder axis and deviate to a lesser extent from the radial directionthan the ports 3, the fresh gases entering through ports 4 (as indicatedin Fig. '7) will move substantially in an annular zone 0 enclosed in theannular zone 0. Within the annular zone c there again remains a core bof waste gas, which is however considerably smaller than the core b inFig. 6.

Thus during the outward stroke of the piston l0 and the gradualuncovering of the consecutive rows of intake ports the core of wastegases is gradually diminished, until, when uncovering the outermost rowof ports 6 (Fig. 8), the radially entering scavenging gases meet inthecenter of the piston bottom and are thus deflected in the direction ofthe cylinder axis, whereby also the innermost core of waste gases isaltogether expelled from the cylinder space.

Thus the new arrangement of the intake ports results in a very completeexpulsion of the waste gases from the interior of the working cylinder.

During the return stroke of the piston It! the row of ports 3, the axesof which deviate mostly from their radial direction, is the last to becovered. In consequence of this the scavenging gas current is impartedup to the end a powerful rotatory impulse, so that the fresh gasespresent in the cylinder, after the intake ports have been closed, willowing to their inertia rotate further. This rotatory movement of thefresh gases greatly favors the intimate mixture of the air of combustionwith the fuel, which may for instance be injected into the cylinderthrough a nozzle l2. This shows that both requirements defined above arefulfilled by the invention.

Various changes may be made in the details disclosed in the foregoingspecification without departing from the invention or sacrificing theadvantages thereof.

I claim:

i. In an internal combustion engine having a cylinder, a piston operablein said cylinder and exhaust ports; an exhaust gas scavenging systemcomprising means for progressively passing at difierent angles withrespect to the longitudinal axis of said cylinder scavenging gas intoadjacent portions of the interior of said cylinder and with a swirlingmotion toward said exhaust ports whereby exhaust gases are scavengedwithout admixture with the'turbulent intake gases.

2. In an internal combustion engine having a cylinder including acombustion chamber, a piston movable in said cylinder along thelongitudinal axis thereof, and exhaust ports; a plurality of rows ofintake ports-arranged peripherally of said cylinder, the axes of theports of each row being of different inclination with respect to saidlongitudinal axis, and the radii of the cylinder, than the axes of theports of the adjacent rows, said inclination of said port axes withrespect to said radii of said cylinder being the greater the nearer therespective row of ports lies to said exhaust ports and with respect tosaid axis being less the nearer the row of ports lies to said exhaustports.

. cylinder and at a different angle to a plane perpendicular to saidaxis, and means to supply scavenging gas to said spaced means.

4. In an internal combustion engine having a cylinder, a piston movablein said cylinder, and exhaust ports located at one end of said cylinder;a plurality of rows of inlet ports arranged at the other end of saidcylinder, said rows of inlet ports being spaced from each other in adirection longitudinally of said cylinder, a first row of said inletports having the axes of said ports inclined with respect to thelongitudinal axis of said cylinder to direct inlet gas toward saidexhaust ports and further inclined with respect to the radii of theplane of the circle in which said first row lies to direct inlet gas ina first path adjacent and parallel the inner wall of said cylinder, asecond row of said inlet ports having the axis of said ports eachinclined with respect to said longitudinal axis at an angle greater thanthe inclination of theaxes of said first row of ports, said axes of saidsecond row of ports being further inclined to direct said inlet gases ina second path adjacent and parallel to said first path, and at least athird row of said inlet ports having the axis of each port inclined-withrespect to said longitudinal axis at an angle greaterthan theinclination of the axis of said second row of ports, and furtherinclined to direct inlet with-respect to the axes or the ports inadjacent gas in at least athirdpath lying inwardly of and parallel tosaid second path.

5-. In an internal combustion engine having a cylinder, a piston movablein said cylinder, and exhaust ports; and exhaust gas scavenging systemcomprising at least three rows of intake ports spaced from each otherand from said exhaust ports longitudinally of said cylinder and adaptedto be successively covered and uncovered by said piston, the axes of therespective ports in one row of said intake ports being diflerentlyinclined rows both with respect to a plane containing the longitudinalaxis of the cylinder and the radii of said cylinder whereby intake gasesenter said cylinder from each row of intake ports as they are uncoveredsuccessively by said piston to scavenge separate portions of saidcylinder, and exhaust gases are scavenged without mixing with intakegases while the intake gases are in turbulent state for mixing withinjected fuel.

7 MANFRED GERLACH.

